None of them is really satisfactory, because none of them posits Romney concealing any facts more harmful than the blowback he is getting for not producing more returns. The problem may be that all of the prominent theories (with a couple of under-noticed exceptions) assume Romney is trying to conceal facts about his finances. Like the purloined letter pinned prominently in plain sight, what Romney's really hiding might be something more mundane: the home address written on the top of the tax form. That address that might reveal a connection between the "tax returns" brouhaha and the "voter fraud" fizzle – which may be the strongest explanation of all. Here's why.